The invention relates to intermediates useful in the preparation of 6-fluoro-7-halo-quinolonecarboxylic acid intermediates for the preparation of 6-fluoro-7-substituted-quinolonecarboxylic acids having antibacterial activity, and to processes for the preparation of such intermediates.
In general, the antibacterial 6-fluoro-7-substituted-quinolone-carboxylic acids are prepared by substitution of the corresponding 7-halo-6-fluoroquinolonecarboxylic acid intermediates wherein the halo atom is preferably fluoro or chloro. Prior art methods for preparing such 7-halo intermediates are described in U.S. Pat. Nos. 4,563,459 and 4,623,650.